Fail-safe throttle control

ABSTRACT

The invention relates to a fail-safe throttle control mechanism which is positioned between an accelerator pedal of a motor vehicle and the linkage extending to the carburetor thereof and includes a sensing mechanism for disengaging the accelerator pedal from the throttle valve so that the engine of the motor vehicle can instantly return to an idle condition irrespective of any impairment in the carburetor linkage or blockage of the accelerator pedal. There are disclosed various embodiments for achieving this fail-safe throttle control through electrical as well as mechanical mechanisms.

ijnited States Patent [191 MacMillan 1 May 8, 1973 [54] FAIL-SAFE THROTTLE CONTROL [76] Inventor: Charles W. MacMillan, 3400-20th St. Ct., Rock Island, 111. 61201 [22] Filed: June 15, 1971 21 Appl. No.: 153,330

Related US. Application Data [63] Continuation-impart of Ser. No. 88,450, Nov. 10,

1970, Pat. No. 3,626,919.

[52] US. Cl. ..l23/198 DB, 123/98, 180/82, 192/3 R, ZOO/61.9, 192/3 R [51] Int. Cl ..F02b 77/00 [58] Field of Search ..74/512, 513; 123/198 R, 198 DB;180/82, 103,105; ZOO/61.89, 61.9, 161; 340/53; 192/3 R [56] References Cited UNITED STATES PATENTS 3,313,897 4/1967 Gorsky ..200/61.89

8/1967 Hollins ..192/3 R 3,338,357 3,435,165 3/1969 Lombard ..200/61 .89 3,487,183 12/1969 Schulman ..200/61.89

Primary Examiner-Charles J. Myhre Assistant ExaminerRandall Heald Attorney-Edwin E. Greigg [57] ABSTRACT The invention relates to a fail-safe throttle control mechanism which is positioned between an accelera' tor pedal of a motor vehicle and the linkage extending to the carburetor thereof and includes a sensing mechanism for disengaging the accelerator pedal from the throttle valve so that the engine of the motor vehicle can instantly return to an idle condition irrespective of any impairment in the carburetor linkage or blockage of the accelerator pedal. There are disclosed various embodiments for achieving this fail-safe throttle control through electrical as well as mechanical mechanisms.

23 Claims, 13 Drawing Figures PATENTED W 3 SHEET 1 [1F 5 v INVENTOR CHARLES w. MocMlLLAN PAIENTEUMM 8 m3 SHEET 2 [IF 5 PATENTED 81973 I 3.731.667'

SHEET 3 OF 5 PATENTED 81975 3, 731 ,667

sum n []F 5 FAIL-SAFE THROTTLE CONTROL This application is a continuation-in-part of my earlier application for patent filed Nov. 10, I970, Ser. No. 88,450, which was entitled FAIL-SAFE THROTTLE CONTROL and issued as US. Pat. No. 3,626,919 on Dec. 14,1971.

In the earlier application there are disclosed multiple species'of a system which basically teaches the concept of how to deactivate the engine of a motor vehicle when the accelerator linkage becomes impaired thus preventing proper operation because of jamming or freezing of the linkage, disconnection of parts, foreign objects interfering with the accelerator pedal, failure of the throttle lever return spring, such as by breakage thereof, as well as movement of the engine on its mounting means by rapid deceleration.

As was disclosed in my earlier application and is also true in this application, it is of particular concern that the engine speed of the motor vehicle be at least returned to an idle condition when some impairment such as that mentioned above takes place, for it is vitally essential to the continued operation of the engine such with the motor vehicles of today, since they include power accessories, such as brakes and steering that operate off the power of the engine or vacuum of the manifold and these would otherwise be practically useless without the engine running.

THE INVENTION Accordingly, the principal object of this invention is to incorporate into the linkage system extending from the accelerator pedal to the throttle plate lever of a fearburetor, a trigger mechanism which is capable of sensing an operator's act of deceleration of a motor vehicle and compensating for any unknown impairment in the linkage by instantly returning the throttle plate lever to idle.

Another object of this invention is to provide for operation of the trigger mechanism by both mechanical and/or electrical means.

Still another object of this invention is to provide a throttle plate lever linkage system for use in motor vehicles which has incorporated therein a second trigger mechanism.

A still further object of this invention is to include in the electrical system for actuation of the throttle plate lever a circuit breaker arranged to be operated by the accelerator pedal.

Yet another object of this invention is to incorporate into the linkage system and the electrical elements combined therewith a solenoid member that is arranged to operate the trigger means either by a pull or push operation thereof.

Further objects and advantages will become more apparent from a reading of the following specification taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side elevational view of the preferred embodiment of the invention showing the manner of connecting a throttle plate lever to an accelerator pedal which includes dual pivot points;

FIG. 2 is an end elevational view looking in the direction of the arrow in FIG. 1;

FIG. 3 is a side elevational view of the preferred embodiment with the trigger means having been operated to return the throttle plate lever to idle;

FIG. 4 is a side elevational view of the accelerator pedal as it appears when the trigger mechanism assumes the status position shown in FIG. 3;

FIG. 5 discloses a cross-sectional view of an alternative form of trigger actuator shown in FIG. 1;

FIG. 6 is a partial schematic view in side elevation of the accelerator pedal and its cooperating elements when jammed by an object shown in dotted outline;

FIG. 7 shows schematically a partial cross-sectional and partial elevational view of another embodiment of the invention which utilizes a single pivot system for the accelerator pedal member;

FIG. 8 is a generally schematic view of another embodiment of this invention in a passive form;

FIG. 9 is also a schematic view of the embodiment of the invention of FIG. 8 wherein the mechanism is in an active state;

FIG. 10 shows schematically another embodiment of the invention where the accelerator pedal is pushoperated;

FIG. 1 1 is a generally schematic view of another embodiment of this invention in side elevation showing the mechanical operating mechanism for the trigger element;

FIG. 12 is a top plan view of the trigger mechanism for operating the throttle plate lever; and

FIG. 13 is a partial top plan view of a second trigger element for mechanically operating the first trigger element.

Turning now to FIG. 1, there is disclosed in dotted outline at 10 a conventional two barrel carburetor of the type used generally on'present day motor vehicles which as shown in FIG. 2 includes a throttle plate body portion 12, the valve members being shown in dotted outline at 14. The throttle shaft 16 to which the valve members 14 are secured in a known manner projects outwardly of the carburetor and has mounted thereon a throttle plate lever 18, the purpose and function of which is known to those skilled in the art.

As is well shown in FIG. 2, the throttle plate lever means 18 includes integral oppositely offstanding flange portions, one of which is screw-threaded and provided with a slow idle adjusting screw 20, and the other of which functions as the means by which the idle control linkage is operated.

The throttle plate lever is provided with a rigid trigger-type latching member 22 that extends into a perforation 24 formed in the oscillatable lever 26 which is also carried on the throttle shaft 16, the purpose and function of which will now be described. From the view in FIG. 2 it will be noted that the support of the latching member includes a quadruple malethreaded portion 27 which extends into and cooperates with a complementally formed female-threaded portion provided in the body 28. Cooperation between these male and female threaded portions is controlled by the pin 30 while the spring 32 urges the threaded body 28 away from the throttle plate lever 18.

Referring once again to FIG. 1 it will be seen that lever 26 is provided with oppositely extending ears 38-38, the upper one of which is perforated and adapted to receive the movable lever 40 to which is attached at 42 the slidable cable 44 that first enters the sleeve 46 and then the telescoped tubular body 48 and terminates in the perforation at the hooked end of the arm 50 of the accelerator pedal 52, as shown. The

telescoped tubular body 48 is securely attached at one end to a member 54 affixed to the fire wall 56 of the motor vehicle and at the other end to a suitable bracket 58 mounted conveniently and rigidly between the tire wall and the carburetor. It will be noted that the bracket 58 includes perforated ear 60 to which is attached the throttle lever return spring 63, the other end of the spring being secured in the perforation of the tab 62 carried by one car 38.

It is believed to be now apparent to those skilled in the art that the elements thus far described, if nothing more were included, would serve to drive the motor of the motor vehicle by accelerating and decelerating the same through actuation of the accelerator pedal 52.

The elements now to be described which, when taken together with the redesigned elements which could alone serve for proper power control of the motor vehicles power plant will provide a foolproof construction that will prevent inadvertent run-away of an automobile and possible consequent damage, destruction or ultimate death from an accident.

Turning now to the right-hand portion of FIG. 1, one observes that the accelerator pedal 52 is affixed to an angular arm 64 which is pivoted at 66 between the perforated wings (one shown) of a member 68 which, in turn, is pivotally mounted at 67 relative to the fire wall 56 by a bracket 69.

Also, as shown in this view, the flat face 76 of the winged member is arranged to abut an adjustment means 78 that functions as a stop for forward motion of the flat face 76 of the pivotal member 68, the need for which will be understood later herein.

A housing 80 for an electrical circuit making and breaking element 82 is positioned against the fire wall 56 in the engine housing (not shown) and retained by any suitable means such as that shown at 84. In its simplest form of the invention the perforated member that serves to retain the circuit breaker housing 80 relative to the fire wall also functions as a guide means for the circuit breaker actuator 85, this element being adjustable in length and having one end in abutment with the spring-urged arm 86 carrying electrical contact member 88 and the other end in contact with the flat face 76, whereby the first electrical contact 88 will be maintained, during normal acceleration, out of contact with the other electrical contact element 90.

The contact 90 of the electrical circuit breaker 82 is grounded as shown and a lead 92 which is connected to contact 88 extends to the solenoid 94 which, in turn, is

electrically connected to the vehicle battery 96, the

latter being grounded, as shown at 98. The reciprocable plunger 100 is pivotally attached at 102 to a slotted arm 104, the opposite free end of which is threaded at 106 and adapted to receive the elongated rod 108, the terminal end of which is affixed to pin 30, as shown, and for a purpose that will be understood later. The normal movement of slotted arm 104 is free from interference by pin 110 as adjusted by element 112, one end of which is attached by a tab 113 to the fire wall 56, and the other end of which is secured to the pivotal arm 1 14 carrying the guide pin 110. The necessity for this design will be explained later.

As thus far described it is believed to be clear that during normal operation of the motor vehicle the failsafe system remains in a passive non-influential condition with the accelerator pedal serving to accelerate and decelerate the vehicle by means of the elements described to maintain the electrical contacts 88 and 90 out of contact, and the rod 108 and latch 22 moving unrestrained with the linkage.

However, should various types of failure appear in the mechanism which is required for normal operation of the vehicle, such as will now be described, the electrical contactsare brought into engagement as shown in FIG. 4, this operation serving to retract the plunger of the solenoid into its housing and causing the rod 108 to pull the pin 30 forwardly thereby rotating body 28 against spring 32 and withdrawing the latch 22 from lever 26 so that the throttle will instantly return to idle.

Following is a summary of any number of contingencies which the mechanism detailed herein can compensate for and serve to return the throttle to an idle condition.

It is a well known fact that many mothers carry small children either to school as well as to the store and various other places and it is also known and an accepted fact that these children frequently carry toys and throw them around in the motor vehicle while it is being driven. Should it so happen that a small toy or even a stick becomes lodged between the fire wall and the accelerator pedal arm 64 and even though the mother is unaware of its blocking action until she removes her foot from the accelerator pedal 52 and begins to apply the brakes, whereupon in normal vehicle construction the automobile would continue to accelerate, she could not in all probability remove the obstacle without bending down and consequently removing her eyes from the highway, thus in all likelihood causing an accident. In a motor vehicle equipped with the fail-safe throttle control mechanism described herein, the blocking action on the accelerator pedal arm would be immediately sensed upon an attempt to decelerate, with the result that the pressure upon the pin would be removed, thus enabling the electrical contacts 88 and to close with the consequent sequence of events described earlier herein taking place and the throttle returning to an idle position.

In a condition either where the cable 44 for some unknown reason fails or becomes disconnected from the arm 50 or the spring 63 breaks, there will be no pulling force exerted at the point 66 in the absence of accelerator pedal pressure with the result that the spring 86 will urge the pin 85 outwardly against the bracket 68 thereby removing pressure from the pin 85 and causing the electrical contacts to close.

In still another contingency where the engine may move forward on its mounting elements due to rapid deceleration or other causes, the entire linkage except those not attached to the engine of the motor vehicle will move forward with the engine. As noted earlier herein the adjustable rod 112 is secured to the tire wall by a bracket 113 thus providing a rigid structure which will not move with the engine, the ultimate effect being the same as pulling rod 112 in the direction indicated by the arrow A. It is to be understood that in normal operation of the motor vehicle and with a wide open throttle position, pin 110 is just in contact with the end wall of the slot and accordingly, movement of the engine forward, carrying with it the pivotal lever 114 as well as the solenoid parts described, results in operating the rod 108 pulling it rearwardly toward the fire wall and causing the latch member 22 to be removed from the lever 26 as explained, whereupon the throttle will return to idle condition. Under conditions as those such as have been just narrated, this action occurs mechanically without any activation of the solenoid and the operation is augmented by but not dependent upon the torsion spring 34 which surrounds the throttle shaft 16.

In view of the foregoing explanation it is believed now to be clear to one who has read the specification how various other adaptations of the teaching can be utilized. With this in mind reference is made at this time to the schematic view in FIG. 6 wherein a pushrod type of throttle control includes an accelerator pedal 120 which is actuated in the direction of the arrow 122 depicting acceleration of the motor vehicle by means of the force 122 this operating to push against the normal throttle closing force exerted in the direction indicated by the arrow 124. The pivot points 66 and 67 function together with the actuator 85 described earlier herein to retain the electrical contacts 88 and 90 out of engagement until some contingency takes place as explained earlier herein.

In the simplified schematic view of FIG. 7 there is disclosed a passive condition of the fail-safe throttle control system in which the throttle plate lever 18 and the pivotal lever 26 are shown in spaced relation in an in line-condition for clarification, and a trigger latch mechanism constituted by a pair of jaws 130 and 132 which are adapted to grasp pivot 134, thus permitting the throttle lever to operate normally. The function of the solenoid having already been eluded to it will suffice to indicate that upon abnormal operation the solenoid will serve to pull rod 108 rearwardly causing toggle lever arms 136136 to open, thus releasing the pivot 134 and causing the throttle plate to return to an idle condition. This is clearly shown in FIG. 8.

It is believed to be apparent from the foregoing that the basic system described herein may be implemented in various forms and combinations of functional elements. For example, specific arrangements encompassed include the following which will be readily understood by those skilled in the art and after having studied the specification.

The accelerator sensing means, namely pivots 66 and 67, and its cooperating actuator 85 may be replaced by a single pivot and pedal arm assembly for operating electrical contacts 88 and 90 or a pressure switch as well as a transducer. In this construction the pivot support is sufficiently flexible to permit actuation of the switch or other sensor when pressure is released. A downward extension of pedal arm 64 below said single pivot arranged to contact a fixed stop as the pedal is released provides leverage to hold the switch or other similar element open or inactive when the pedal is normally released. This leverage is effected as previously explained by tension in the cable 44 and the resistance of the spring 86 provided in the electrical contact housmg.

It is also contemplated that the solenoid 94 and pull rod 108 although shown as a linear motion assembly may be replaced by a rotary solenoid, the latter adapted to be mounted concentrically with the throttle shaft 16, at which time no spring such as 34 would be used.

In this concept the housing of the rotary solenoid is adapted to be fixed preferably by a bracket arm fastened to the carburetor and positioned between throttle plate lever 18 and the cooperating pivotal lever 26. In such a design throttle plate lever 18 is connected with the rotary armature through the pivotal lever adapted to operate the trigger latch device which holds these respective elements rotationally together under normal conditions and as previously explained.

Although the description of the preferredembodiment has eluded to a solenoid and electrical contacts for causing the throttle plate to return to an idle condition under certain contingencies outlined hereinbefore, it is to be understood that an entirely mechanically operated system is also contemplated and this is shown in the remaining views in the drawings.

In the embodiment of the invention shown in FIGS. 10-12, the partial side elevational and cross-sectional view of FIG. 11 will be initially referred to for a better understanding of this concept.

For an expedient understanding of the mechanical equivalent of the electrical embodiment described earlier herein, it is best to note that all of the elements to the left of the bracket 58a shown in FIG. 11, as one looks into the drawing, are substantially the equivalent of the electrical embodiment and those extending to the right of this bracket up to the fire wall constitute the mechanical means which are substituted for the electrical features described.

The bracket 58a as explained earlier is rigidly mounted in the engine compartment in any suitable manner and forms the base for one end wall of spring 140, its other end being in abutment with plurally perforated arm 141 which is pivotally mounted in a rigid support 142, the perforation 143 arranged to receive the rod 108 which extends to the latch mechanism as explained earlier.

Reference at this time to FIG. 13 will provide a better understanding of the trigger latch mechanism and its function.

The perforation 144 in the pivotal arm 141 is arranged to receive the oscillatable trigger latch 145, the function of which is the full equivalent of the latching means described earlier as that utilized to disengage the throttle plate lever 18 from the lever 26. In the embodiment of the invention identified as FIG. 2, the terminus of pin 30 cooperates with the staked quadruple male thread member 27 which extends into the femalethreaded body 28. Of course, in this later embodiment of the invention it is also necessary for this pin 146 to be mounted on a rigid support 150 (see FIG. 13).

The operating means for this second trigger latch is constituted by a linkage which includes the pin a adapted to sense the condition and position of the pivot means 68 for the accelerator pedal 52 with the pin, in this instance, including a stop means 147 for a coil spring 148, which is interposed between the stop means and a rigid bracket 149.

It is believed to be apparent from this description that in the event of some mechanical failure of the elements constituting the accelerator mechanism for the motor vehicle to function properly upon deceleration, the spring 148 will sense the failure and push the stop means 147 toward the fire wall, thus disengaging the latch means from lever 141, and substantially simultaneously the spring 140 will snap the pivotal arm 141 toward the fire wall, thus pulling on rod 108 and releasing the latch 22 from the oscillating lever 26.

Many vehicle manufacturers usually offer as optional equipment automatic speed control systems and it is contemplated that each of the electrically operated fail-safe throttle systems disclosed herein or the mechanical equivalent thereof and this concept may be utilized with such systems. This addition to such a system can be achieved by use of a simple switching means whereby the fail-safe system is automatically bypassed when the speed control is in use. This is accomplished by connecting a second normally closed switch in series with the electrical contacts 88 and 90. This second switch is arranged to be opened simultaneously with engagement of the speed control system thus preventing the released pedal condition from actuating the fail-safe system. Upon disengagement of the automatic speed control system, the second switch is automatically closed thus re-arming the fail-safe system.

Although it is believed that the system previously described in connection with the automatic speed control system is most simplified, it is also contemplated and possible to condense the elements which constitute the fail-safe throttle control mechanism into a utilized design and then merely position it in the linkage arrangement ahead of the speed control system. This method, of course, requires duplicate sensing members for the speed control unit and the accelerator pedal. A single-pole double-throw switch may be automatically engaged to activate one or the other of the sensing assemblies, each of which includes contact points 88 and 90.

What is claimed is:

l. A fail-safe throttle control mechanism for internal combustion engine carburetors including a carburetor mounted on a motor vehicle comprising throttle plate lever means including a first trigger means cooperating with means adjacent to said throttle plate lever means, plural means extending from said last named means and operatively connected to an accelerator pedal, and further means interposed between the accelerator pedal and one of said plural means for operating the trigger means to disconnect the accelerator pedal from the throttle plate lever means.

2. A fail-safe throttle control mechanism as claimed in claim 1, wherein the throttle plate lever means and the means adjacent thereto are operatively interconnected by spring means.

3. A fail-safe throttle control mechanism as claimed in claim 2, wherein the spring means is arranged for relative opposite rotation of the elements with which it is operatively associated.

4. A fail-safe throttle control mechanism as claimed in claim 1, wherein the trigger means is disengaged from the means adjacent to the throttle plate lever means by electrical means.

5. A fail-safe throttle control mechanism as claimed in claim 1, wherein the trigger means is disengaged from the means adjacent to the throttle plate lever means by a second trigger means.

6. A fail-safe throttle control mechanism as claimed in claim 4, wherein the electrical means include switch means.

7. A fail-safe throttle control mechanism as claimed in claim 4, wherein the electrical means includes solenoid means.

8. A fail-safe throttle control mechanism as claimed in claim 7, wherein the solenoid means is associated with said further means for operation of the trigger means.

9. A fail-safe throttle control mechanism as claimed in claim 7, wherein the solenoid means is associated with said further means for pull operation of the trigger means.

10. A fail-safe throttle control mechanism as claimed in claim 1, wherein the accelerator pedal includes pivotal means cooperating with actuator means for said electrical means.

1 l. A fail-safe throttle control mechanism as claimed in claim 1, wherein the trigger means is retained in passive condition by pivotal toggle arm means.

12. A fail-safe throttle control mechanism as claimed in claim 11, wherein the toggle arm means are solenoid-operated.

13. A fail-safe throttle control mechanism as claimed in claim 5, wherein the first trigger means includes a second trigger means.

14. A fail-safe throttle control mechanism as claimed in claim 13, wherein the second trigger means is actuated by linkage means associated with the accelerator pedal 15. A fail-safe throttle control mechanism as claimed in claim 14, wherein the second trigger means cooperates with pivotal arm means.

16. A fail-safe throttle control mechanism as claimed in claim 15, wherein the pivotal arm means include the further means for actuating the trigger means.

17. A fail-safe throttle control mechanism as claimed in claim 1, wherein the trigger means is retracted from said further means in a plane extending normal to said further means.

18. A fail-safe throttle control mechanism as claimed in claim 9, wherein the said further means includes unidirectional slip joint members.

19. A fail-safe throttle control mechanism as claimed in claim 4, wherein the electrical means includes plural switch means.

20. A fail-safe throttle control mechanism as claimed in claim 19, wherein at least one of said switch means is opened simultaneously with engagement of an automatic speed'control system.

21. A fail-safe throttle control mechanism as claimed in claim 1, wherein the accelerator pedal includes single pivot means.

22. A fail-safe throttle control mechanism as claimed in claim 1, wherein the accelerator pedal includes plural pivot means.

23. A fail-safe throttle control mechanism as claimed inclaim 9, wherein the further means for pull operation of the trigger means comprises a flexible means. 

1. A fail-safe throttle control mechanism for internal combustion engine carburetors including a carburetor mounted on a motor vehicle comprising throttle plate lever means including a first trigger means cooperating with means adjacent to said throttle plate lever means, plural means extending from said last named means and operatively connected to an accelerator pedal, and further means interposed between the accelerator pedal and one of said plural means for operating the trigger means to disconnect the accelerator pedal from the throttle plate lever means.
 2. A fail-safe throttle control mechanism as claimed in claim 1, wherein the throttle plate lever means and the means adjacent thereto are operatively interconnected by spring means.
 3. A fail-safe throttle control mechanism as claimed in claim 2, wherein the spring means is arranged for relative opposite rotation of the elements with which it is operatively associated.
 4. A fail-safe throttle control mechanism as claimed in claim 1, wherein the trigger means is disengaged from the meaNs adjacent to the throttle plate lever means by electrical means.
 5. A fail-safe throttle control mechanism as claimed in claim 1, wherein the trigger means is disengaged from the means adjacent to the throttle plate lever means by a second trigger means.
 6. A fail-safe throttle control mechanism as claimed in claim 4, wherein the electrical means include switch means.
 7. A fail-safe throttle control mechanism as claimed in claim 4, wherein the electrical means includes solenoid means.
 8. A fail-safe throttle control mechanism as claimed in claim 7, wherein the solenoid means is associated with said further means for operation of the trigger means.
 9. A fail-safe throttle control mechanism as claimed in claim 7, wherein the solenoid means is associated with said further means for pull operation of the trigger means.
 10. A fail-safe throttle control mechanism as claimed in claim 1, wherein the accelerator pedal includes pivotal means cooperating with actuator means for said electrical means.
 11. A fail-safe throttle control mechanism as claimed in claim 1, wherein the trigger means is retained in passive condition by pivotal toggle arm means.
 12. A fail-safe throttle control mechanism as claimed in claim 11, wherein the toggle arm means are solenoid-operated.
 13. A fail-safe throttle control mechanism as claimed in claim 5, wherein the first trigger means includes a second trigger means.
 14. A fail-safe throttle control mechanism as claimed in claim 13, wherein the second trigger means is actuated by linkage means associated with the accelerator pedal.
 15. A fail-safe throttle control mechanism as claimed in claim 14, wherein the second trigger means cooperates with pivotal arm means.
 16. A fail-safe throttle control mechanism as claimed in claim 15, wherein the pivotal arm means include the further means for actuating the trigger means.
 17. A fail-safe throttle control mechanism as claimed in claim 1, wherein the trigger means is retracted from said further means in a plane extending normal to said further means.
 18. A fail-safe throttle control mechanism as claimed in claim 9, wherein the said further means includes unidirectional slip joint members.
 19. A fail-safe throttle control mechanism as claimed in claim 4, wherein the electrical means includes plural switch means.
 20. A fail-safe throttle control mechanism as claimed in claim 19, wherein at least one of said switch means is opened simultaneously with engagement of an automatic speed control system.
 21. A fail-safe throttle control mechanism as claimed in claim 1, wherein the accelerator pedal includes single pivot means.
 22. A fail-safe throttle control mechanism as claimed in claim 1, wherein the accelerator pedal includes plural pivot means.
 23. A fail-safe throttle control mechanism as claimed in claim 9, wherein the further means for pull operation of the trigger means comprises a flexible means. 